You might have heard people talking about grow lights lately, but do you know what they are, how they work, or what kind you need? We've assembled a grow light guide for you so you can make the best choices for your indoor seedlings, winter herbs, and more.

How do grow lights work?

Plants grow and stay healthy through photosynthesis, a pretty amazing chemical process. As long as they've got chlorophyll (that stuff that makes them green), a light source, water and nutrition, they're sitting pretty. But indoors, there's not necessarily a lot of light — especially in the winter or in dark areas of the home.

Enter grow lights. These lamps mimic daylight so plants get more time in the sun (so to speak). Grow lights can be used for timing and forcing seedlings, commercial hydroponic crop production, growing plants in the winter in dark locales, and a whole lot more.

When is a grow light necessary?

Whether you need a grow light depends on what you're growing, when you'd like to grow it, and where. If your house is dim or you want to grow plants in spots like the bathroom and the basement, they'll need the extra light to thrive. If you want to grow in the winter months, you'll need more light to make up for the lost daylight hours. If you'd like to try your hand at forcing plants to grow out of season or growing plants native to regions with longer days, a grow light can be a good idea.

What bulbs are best?LED Grow light

While any light can technically work as a grow light, halogen and incandescent bulbs usually run too hot to be safe. CFLs and LED bulbs, on the other hand, run cool, provide a broad spectrum of light, and — best of all — offer a lot of light with low energy use. Since your goal is very bright light, this is a big bonus!

You do need to pay attention to the spectrum of light emitted by the bulb. Plants like lots of light on blue and red wavelengths. They don't want a red party bulb, but they'd appreciate a full spectrum light bulb to help them grow, and develop even, bushy forms rather than more leggy ones. Full spectrum bulbs can be a little more expensive, but they're worth it!

The great thing about using these basic commercial bulbs is that they fit into ordinary light fixtures. You can even use gooseneck lamp and a single LED bulb angled to bathe them in lots of light. This is an affordable and minimally disruptive way to use a grow light around the house.

What about high-end grow lights?

High-end grow lights specifically designed for this purpose are also available, including both bulbs and fixtures. They tend to be bulky, because they are designed for people and nurseries growing large numbers of plants. They're very bright, but they're also very expensive, and they tend to be huge energy suckers. In fact, you usually need a specialized electrical system with an enhanced load drop and dedicated breaker box to supply their energy needs. Unless you're planning on filling the guest room with tomatoes, you probably don't need one of these.

Don't forget to turn them off! Plants growing under lights

Your grow lights should be off for at least eight hours a night unless a plant has special needs. You can turn them off on your own, but most people use a timer. Timers are extremely inexpensive and easy to program, and they'll provide you with total control.

Placement is key

Make sure to experiment with distancing, because if the lamp is too close, it can be too intense for your plants. Keep it away from flammable furnishings in case there's an accident, and remember: that intense light can be unpleasant when you're watching movies, going to bed, or entertaining guests, so consider the location of your grow light carefully.

Katie Marks originally wrote this story for Networx.com. It has been republished with permission here.

Related stories on MNN:

LED light photo credit: nikkytok/Shutterstock

Plants photo credit:MissMessie/Flickr